Method of forming lock washers



July 1, 1941- c. c. WA HER" METHOD OF FORMING LOCKYWIASHERS Filed Feb.2, 1940 2 Sheets-Sheet 1 July 1, 1941 c. c. WASHER 2,247,981

METHOD OF FORMING LOCK WASHERS Filed Feb. 2, 1940 2 Sheets-Sheet 2Patented July 1, 1941 Chandler C. Washer, Merion, Pa., assignor toPhiladelphia Steel and Wire Corporation, Philadelphia, Pa., acorporation of Pennsylvania Application February 2, 1940, Serial No.317,015

4 Claims.

This invention relates to a method of producing non-entangling lockwashers and, more particularly, to producing such washers in the formshown in my copending application Serial No. 263,524, filed March 22,1939, for Lock washer.

An important object of the invention isthe production of a method ofproducing such lock washers which will render the same non-entangling ina normal method of formation thereof.

A more particular object of the invention is the production of washersof this type by a method in which the materials themselves serve topre-tension the helical coil from which the washers are formed so thatupon separation of the individual washers the ends of the washer willspring toward one another to an extent such that interlinking of thewashers is prevented provided the gap between the ends thereof is notmade excessive.

A still further object of the invention is'the production of a method ofthis character which will enable considerably more latitude formechanical errors in construction insofar as the length of the helix isconcerned, thus materially reducing the number of washers which arefailures due to the fact that their ends do not come into properrelation.

These and other objects I attain by the construction shown in theaccompanying drawings wherein, for the purpose of illustration, I haveshown a preferred embodiment of my invention and wherein:

Fig. 1 is a plan view of a lock washer produced in accordance with myinvention;

Fig. 2 is a side elevation thereof;

Fig. 3 is a sectional view through the washer on line 3-3 of Fig. 1;

Fig. 4 is a perspective view of a fragment of the wire employed inconstructing the washer;

Fig. 5 is a sectional view illustrating the method of forming the coilfrom which the washers are subsequently severed;

Fig. 6 is a plan view illustrating the manner in which the washersengage when an attempt is made to interlink the same;

Fig. 7 is a section on line 'l-'l of Fig. 6;

Fig. 8 is a section on line 8-8 of Fig. 6; and

Fig. 9 is a view showing the increased gap per missible when the washeris formed with angularly cut ends.

Referring now more particularly to the drawings, the washer comprises ahelical coil [0 of substantially 360 degrees, such coil being composedof material having a body portion ll substantially rectangular in crosssection and defined at the inner edges of the transaxial faces thereofby axially shallow and radially narrow ribs I2. The transaxial surfaces13 outwardly of the ribs I2 are preferably parallel and disposed v atright angles to the axis of the helix and the outer surfaces of the ribsthemselves are preferably made arcuate and smooth with the surfaces I3either corrugated or plain as desired.

In constructing such washers I employ a wire of cross section such asshown in Fig. 4; that is to say, a wire of keystone cross sectiontheedges of the converging faces IQ of which are defined at the narrow edgeof the section by outstanding ribs 20 which subsequently produce theribs l2 of the finished washer.

A wire of this cross section is wound about a round mandrel 2| with thenarrow edge 22 of the keystone facing the mandrel. This coiling will, ofcourse-tend to stretch the wider end of the keystone and compress thenarrow inner edge thereof withthe result that the faces l9 come intoparallelism as shown in Fig. '7. The ribs 2|] are slightly rounded andfilleted at their connection with the faces on which they are formed,and in coiling the wire the pitch of the helix 23 formed about themandrel is made such that the last wound coil 24 is spaced from the nextadjacent previously wound coil a distance approximating the width of onerib. The ribs winding upon one another wedge the finally wound coil toone side as shown by the dotted lines at C in Fig. 5, thus placing thecoil under axial tension. Accordingly, when the convolutions of the coilare severed by the usual severing means the axial tension of the coilresults in movement of the severed ends axially so that the rib portionsthereof will overlap. The helix thus resulting will, as regards itsmajor cross section, have less axial pitch than the axial cross sectionof the butt portion. The rib portions, however, will axially overlapwith the result that when a deliberate effort is made to engage two ofthese washers with one another such attempt must fail because ofabutment of the ribs unless the gap has been made excessively wide.

It has been found in practice that the gap usable with such washers canfar exceed that of the ordinary washer of similar cross sectional areaand may be as much as 30 per cent of the smallest axial thickness of thewasher section, when the angle cut of the washer is parallel to the axisof the helix. This gap may be increased as the angle of cut in increaseduntil at a 45 degree angle' it may be made slightly less than per centof the major depth of the washer section, such major depth including thedepth of the ribs.

Obviously, the ability to form a gap so wide as compared to the washercross sectional area results in a considerable saving of material, bothby reason of the fact that less wire is necessary to the formation ofthe washer and that the number of rejections as a result of malformedwashers occurring in normal manufacture may be reduced. This isimportant for, despite the accuracy ofj the present-day machinesemployed in the construction of lock washers, errors occur as a resultof uncoilin movement of the helix prior to severing. Accordingly, ifonly a 15 per cent gap is possible even a slight error resulting from Isuch axial movement or from Wear or other causes might cause the washerto either; be of the linking type or to have its ,endsqso closel-y related that it could not flattenproperly I 7 v s As the methodhereinbefore set forthis capable of some modification without departing,from the spirit of my invention, I do not wish to be understood aslimiting myself thereto except as hereinafter claimed.

' -Ielaimz r r 1; The-method of producing lock washers com-"-prisi-ngproviding a wire of keystone section --the narrow end of whichis defined at each'of the converging faces by a rib projecting from saidface andhelically'coiling the wire about a mandrel withthe narrow endofthe keystone juxtaposed-to themandrel while maintaining the-pitch 5,

of the helix at anangle "such that the rib-of each newly 'lai-d coilbears against the rib of the-previousl-y laid' coil to an' extentsuch-that thenewly laidcoil is moved axiallyby engagen-ieht of'its ribwith that of the previously laid coil prior to engagement of the-innersurface ofthe wire with the mandrel and finally severing the individualcoils-to produce washers. v I J 2. The method of producing lock washerscomprising providing & Wlrelof keysto Section the r r narrowend of whichis defined at each of the converging faces by -aroundedrib projectingfrom said face and helically coiling the wire about a mandrel with thenarrow end of the keystone juxtaposed to the mandrel while maintainingthe pitch of the helix at an angle such that the rib of each newly laidcoil bears against the rib of the previously laid coil to an extent suchthat the newly laid coil is moved axially by engagement of its rib withthat of the previously laid coil prior to engagement of the innersurface of the wire with the mandrel and finally severing o theindividual coils to produce washers.

ingfthe wire about a mandrel with the ribbed V 3. The method ofproducing lock washers com prising providing a flattened wire oppositefaces ofv which are defined at corresponding edges byribsl'irojectin'gfmm said faces and helically coiledges juxtaposed tothe mandrel while maintaining the pitch of the helix at an angle suchthatthe rib of each newly laid coil bears against the rib of thepreviously laid coil to an extent such that the newly laid coil is movedaxially by engagementofits rib with-that of the previously lai dcoil'prior to engagement of the inner surfaceof the wire with the mandreland finally severing the individual coils to producewa'shers 4.v'I'he'method of producing lock washers comprising providing a flattenedwire opposite faces of whioh 'are defined at corresponding edgesbyrounded ribs projecting from said faces and helically coiling the wireabout a mandrel with-the ribbed edges; juxtaposed to the mandrel whilemaintaininguthe pitch ofv the helix at an angle such. that :the rib of.each newly laid coil bears against ztlie rib of .the previously laidcoil to an extent such that the newly laid coil is moved axially byengagementof-its rib with that of the previously laid coil prior toengagement of the inner surface-of the wire with the mandrel and finallysevering the individual coils to produce Washers.

CHANDLER G. WASHER.

